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. 1988 Feb;118(2):173–180. doi: 10.1093/genetics/118.2.173

Escherichia Coli Mutations That Prevent the Action of the T4 Unf/Alc Protein Map in an RNA Polymerase Gene

L Snyder 1, L Jorissen 1
PMCID: PMC1203271  PMID: 3282983

Abstract

Bacteriophage T4 has the substituted base hydroxymethylcytosine in its DNA and presumably shuts off host transcription by specifically blocking transcription of cytosine-containing DNA. When T4 incorporates cytosine into its own DNA, the shutoff mechanism is directed back at T4, blocking its late gene expression and phage production. Mutations which permit T4 multiplication with cytosine DNA should be in genes required for host shutoff. The only such mutations characterized thus far have been in the phage unf/alc gene. The product of this gene is also required for the unfolding of the host nucleoid after infection, hence its dual name unf/alc. As part of our investigation of the mechanism of action of unf/alc, we have isolated Escherichia coli mutants which propagate cytosine T4 even if the phage are genotypically alc(+). These same E. coli mutants are delayed in the T4-induced unfolding of their nucleoid, lending strong support to the conclusion that blocking transcription and unfolding the host nucleoid are but different manifestations of the same activity. We have mapped two of the mutations, called paf mutations for prevent alc function. They both map at about 90 min, probably in the rpoB gene encoding a subunit of RNA polymerase. From the behavior of Paf mutants, we hypothesize that the unf/alc gene product of T4 interacts somehow with the host RNA polymerase to block transcription of cytosine DNA and unfold the host nucleoid.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ARBER W., LATASTE-DOROLLE C. [Enlargement of the host area of bacteriophage lambda for Escherichia coli B]. Pathol Microbiol (Basel) 1961;24:1012–1018. [PubMed] [Google Scholar]
  2. Bachmann B. J. Linkage map of Escherichia coli K-12, edition 7. Microbiol Rev. 1983 Jun;47(2):180–230. doi: 10.1128/mr.47.2.180-230.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Herman R. E., Haas N., Snustad D. P. Identification of the bacteriophage T4 unf ( = alc) gene product, a protein involved in the shutoff of host transcription. Genetics. 1984 Oct;108(2):305–317. doi: 10.1093/genetics/108.2.305. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Hsu T., Wei R. X., Dawson M., Karam J. D. Identification of two new bacteriophage T4 genes that may have roles in transcription and DNA replication. J Virol. 1987 Feb;61(2):366–374. doi: 10.1128/jvi.61.2.366-374.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Koerner J. F., Snustad D. P. Shutoff of host macromolecular synthesis after T-even bacteriophage infection. Microbiol Rev. 1979 Jun;43(2):199–223. doi: 10.1128/mr.43.2.199-223.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kutter E. M., Bradley D., Schenck R., Guttman B. S., Laiken R. Bacteriophage T4 alc gene product: general inhibitor of transcription from cytosine-containing DNA. J Virol. 1981 Dec;40(3):822–829. doi: 10.1128/jvi.40.3.822-829.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Kutter E., Drivdahl R., Rand K. Identification and characterization of the alc gene product of bacteriophage T4. Genetics. 1984 Oct;108(2):291–304. doi: 10.1093/genetics/108.2.291. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  9. Low K. B. Escherichia coli K-12 F-prime factors, old and new. Bacteriol Rev. 1972 Dec;36(4):587–607. doi: 10.1128/br.36.4.587-607.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Pearson R. E., Snyder L. Shutoff of lambda gene expression by bacteriophage T4: role of the T4 alc gene. J Virol. 1980 Jul;35(1):194–202. doi: 10.1128/jvi.35.1.194-202.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Sinden R. R., Pettijohn D. E. Chromosomes in living Escherichia coli cells are segregated into domains of supercoiling. Proc Natl Acad Sci U S A. 1981 Jan;78(1):224–228. doi: 10.1073/pnas.78.1.224. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Sirotkin K., Wei J., Snyder L. T4 Bacteriophage-coded RNA polymerase subunit blocks host transcription and unfolds the host chromosome. Nature. 1977 Jan 6;265(5589):28–32. doi: 10.1038/265028a0. [DOI] [PubMed] [Google Scholar]
  13. Snustad D. P., Haas N., Oppenheimer D. G. The bacteriophage T4 regulatory protein gpunf/alc binds to DNA in the absence of RNA polymerase. J Virol. 1986 Dec;60(3):1145–1147. doi: 10.1128/jvi.60.3.1145-1147.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Stevens A. New small polypeptides associated with DNA-dependent RNA polymerase of Escherichia coli after infection with bacteriophage T4. Proc Natl Acad Sci U S A. 1972 Mar;69(3):603–607. doi: 10.1073/pnas.69.3.603. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Tigges M. A., Bursch C. J., Snustad D. P. Slow switchover from host RNA synthesis to bacteriophage RNA synthesis after infection of Escherichia coli with a T4 mutant defective in the bacteriophage T4-induced unfolding of the host nucleoid. J Virol. 1977 Dec;24(3):775–785. doi: 10.1128/jvi.24.3.775-785.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Tutas D. J., Wehner J. M., Koerner J. F. Unfolding of the host genome after infection of Escherichia coli with bacteriophage T4. J Virol. 1974 Feb;13(2):548–550. doi: 10.1128/jvi.13.2.548-550.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wilson G. G., Tanyashin V. I., Murray N. E. Molecular cloning of fragments of bacteriophage T4 DNA. Mol Gen Genet. 1977 Nov 14;156(2):203–214. doi: 10.1007/BF00283493. [DOI] [PubMed] [Google Scholar]
  18. Wood W. B. Host specificity of DNA produced by Escherichia coli: bacterial mutations affecting the restriction and modification of DNA. J Mol Biol. 1966 Mar;16(1):118–133. doi: 10.1016/s0022-2836(66)80267-x. [DOI] [PubMed] [Google Scholar]
  19. Wu R., Geiduschek E. P. The role of replication proteins in the regulation of bacteriophage T4 transcription. I. Gene 45 and hydroxymethyl-C-containing DNA. J Mol Biol. 1975 Aug 25;96(4):513–538. doi: 10.1016/0022-2836(75)90137-0. [DOI] [PubMed] [Google Scholar]

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